And brothers in bands? Well, just a short list of scrapping siblings would include Ray and Dave Davies of the Kinks, Phil and Don of the Everly Brothers, John and Tom Fogerty of Creedence Clearwater Revival and, most famously (or just the loudest), Liam and Noel Gallagher of Oasis.

Which is just one more reason why the Avett Brothers duo of Scott and Seth Avett are such a unique pair. As seen in the new HBO documentary, “May It Last: A Portrait of the Avett Brothers,” from Judd Apatow and Michael Bonfiglio, the brothers come off not only as fine, hardworking musicians, but as exemplary siblings, as well .

Filmed over 2 years as they toured and worked on the 2016 album “True Sadness,” the documentary shows the brothers composing together, easily picking up on each other’s work to create songs together. And they address their own relationship, copping to the fact that they couldn’t really imagine working with anyone else in the same way.

(Courtesy of HBO)

Providing some funny stories of them as kids as well as some early live recordings with a loud early band, the documentary mainly sticks with the brothers, their family, their band and crew and producer Rick Rubin. While it doesn’t offer a wide-angle look at the band, it does offer something perhaps more poignant: intimate portraits of their working lives and relationships.

One telling segment shows the brothers cutting firewood with their father (they all live near each other in North Carolina). It’s sweet, funny and unaffected, and their father is an especially delightful added voice to the documentary. He’s both supportive – he says he would like their music even if they weren’t his sons – and a down-to-earth presence who doesn’t appear to have let their success change how he treats them (which, for the record, appears to be quite loving).

The film also addresses life changes, including Seth’s divorce, subsequent relationship with actress Jennifer Carpenter and impending fatherhood, as well as scenes of Scott at home with his wife and children. And in one affecting segment, longtime bassist Bob Crawford, whose young daughter was diagnosed with a brain tumor, discusses his daughter’s condition, living with its results and the band’s unflinching support through the process of treatment and rehabilitation. It’s a powerful, moving document of people who love each other, and an antidote to the usual stories of band infighting or star turns by the brightest lights of a group.

Apatow and Bonfiglio do a fine job creating a portrait that should satisfy fans and serve as an inviting introduction to those who don’t know the Avett’s classic American music.

The documentary hits its peak as we watch the group in Rubin’s studio recording the “True Sadness” album. During “Divorce Separation Blues,” a heart-wrenching song by Seth about the conflicting and conflicted emotions of ending one relationship and beginning another, he wails a litany of self-recriminating lyrics: “I’ve got the tough education / No celebration / Bad communication / Worse interpretation / Love deprivation / Pain allocation / Soul devastation / Cold desolation / Life complication / Resuscitation / Divorce separation blues.” And when he finishes, you can see him exhale as if he’s just relived the raw experience all over again. And as they record the aching “No Hard Feelings,” you can almost feel the air stop moving in the room as Seth sings about the peace he hopes to find at the end of his life. The result leaves both Avetts visibly shaken. Rubin and others attempt to talk to the brothers, who – reeling from the emotions stirred up by the performance – slip outside to get some air.

Together, as always.

‘May It Last: A Portrait of the Avett Brothers’

What: A documentary about the siblings in the hardworking Americana band